Paved and concrete roadways are typically provided with shoulder regions which provide sufficient space to enable vehicles to safely pull off from the roadways for various reasons such as emergency repairs, driver and passenger rest, and parking. Road shoulders are typically supplied in the form of granular aggregate substrates such as gravel, crushed rock, sand, pebbles, crushed shells, crumbed waste rubber and other such materials and mixtures of such materials. Road shoulders comprising such granular aggregate materials must be significantly compacted in order to provide suitably dense matrices to support the weights of vehicles as they transition under some speed from the hard road surfaces to the road shoulders, During construction of new roads or re-surfacing of existing roads, the shoulder regions are prepared and worked by dispensing fresh aggregate materials adjacent the road surfaces after which, the road shoulders are worked to draw the aggregate materials against the road surfaces, then smoothed or groomed, and finally compacted by specialized equipment such as motor graders and self-propelled vibratory compacting rollers. Freshly worked and distributed road shoulders are typically very soft and susceptible to forming deep ruts caused by the wheels of equipment used for the initial grooming steps thereby resulting in uneven compacting and poor shoulder stability after compacting has been completed. Furthermore, the grooming steps often require the mouldboards of motor graders to move spilled or excess granular substrates from the surfaces of newly paved or poured road surfaces to the shoulders thereby often causing gouging, tearing or ripping of the newly paved or poured road surfaces which significantly reduces their durability and longevity. Attempts to solve these problems include the development of devices mountable onto dump trucks or specialized self-propelled equipment as exemplified in U.S. Pat. Nos. 5,304,013, 6,164,866, and 6,612,774, for creating and working road shoulders without requiring the trucks or equipment to leave the road surfaces.
Road shoulders are typically positioned adjacent to man-made ditches or gullies to facilitate water egress from the road surfaces. However, excessive rainfalls often result in the formation of rapidly flowing water channels that cut crevices and fissures into road shoulders thereby causing losses of the granular aggregate substrates into the ditches and gullies resulting in destabilization and deterioration of the road shoulders, thus creating hazardous conditions for vehicles transitioning from the road surfaces to the shoulders. Consequently, such road shoulders require regular periodic maintenance with specialized equipment to reclaim road shoulder substrates washed away into adjacent ditches and gullies, followed by their recycling back onto the road shoulder portions which are then reformed and compacted. For example, road shoulder substrates which have washed away into adjacent ditches and gullies may be recovered and transferred onto the road surface by a motor grader equipped with a gang of disc harrows as exemplified in U.S. Pat. No. 5,810,097, and then transferred back to the road shoulder portion by the grader mouldboard. The reclaimed road shoulders may then be worked and groomed by various types of devices as taught by U.S. Pat. Nos. 4,156,466 and 5,332,331, after which the groomed road shoulders may be compacted. However, such road shoulder reclaiming and reforming operations require at least two or more specialized self-propelled equipment such as motor graders that are provided with selected demountable devices adapted for working road shoulders wherein each operation is performed in a separate pass. Consequently, road shoulder forming and reclaiming operations are costly and time-consuming.
Another problem often encountered during road shoulder reclaiming operations is caused by the presence of debris or alternatively, vegetation that commonly establishes and proliferates at the outer margins of road shoulder surfaces and along their side edges sloping into the adjacent ditches and gullies. Such debris and vegetation are typically pulled in clumps onto road surfaces during the shoulder recovery operation, then redistributed across the new shoulder surfaces formed as the granular aggregate materials are transferred back to the road shoulder regions, and then compacted into the newly formed road shoulders. The presence of debris and/or clumps of vegetation on and in newly worked road shoulders results in uneven compaction thereby resulting in unstable road shoulders that quickly deteriorate and subsequently, more frequently require costly and time-consuming road shoulder reclaiming and grooming operations.